The invention relates to a method for stimulating plant growth, which comprises: (a) placing a transparent material for adjusting or retaining the light spectrum below 500 nm (section A), between 500 to 630 nm (section B), or above 630 nm (section C) between light and photosynthesis receptor of plant and (b) after the light passing through transparent material, the illuminance or photon flux density of section B are lower than section A or section C.
